Growth Performance Of Different Yeast Strains As Affected By PH And Sugar Concentration During Fermentation Of Sugarcane Juice

ABSTRACT

Two yeasts (Saccharomyccs cerevisiae and pichia spp) isolates were used to ferment sugarcane juice separately for 10days at room temperatures. While the initial pH (5.0) of one set of the juice was adjusted using buffer solutions- Na₂HPO₄ and NaH₂PO₄ for 24h, the other set was allowed to ferment for 10days without adjusting the pH. The yeast growth and the sugar concentration also known as the total soluble solids (TSS) were monitored. Using the adjusted pH of 4.5 resulted in increased growth of yeast cells with a reduction in total sugar concentration (TSS), from 8% to 4.2%. There was a significant pH decrease in both Pichia fermented and Saccharomyces fermented juice by day 1. The rate of sugar decrease was faster with Saccharomyces fermented than Pichia fermented juice. There was a gradual increase in both Saccharomyces and Pichia yeast cells fermented juices. Pichia (3.5x10⁵cfu/ml) inoculated juice with pH of 5.0 had an increase in TSS by day 1. Thereafter, existed reduced TSS with gradual increase in yeast cells until the 10^thday. Sacchaminyces inoculated juice had more TSS of 1.8% brix at the last day than Pichia.